A photo of Subsea 7's vessel next to a wind turbine at sea

Vattenfall, Subsea 7 Sign Hollandse Kust Zuid Deal

Subsea 7 has signed a contract with Vattenfall for the developer’s four offshore wind farms at the Hollandse Kust Zuid zone in the Netherlands.


Subsea 7 will transport and install 140 monopile foundations and 315 kilometres of 66 kV inner-array cables.

Offshore installation is scheduled for 2021 and 2022. The company will carry out the works using Seaway 7’s heavy lift, cable lay and support vessels.

The contract is subject to Vattenfall’s final investment decision.

In 2019, Vattenfall contracted Seaway 7 for work on the Hollandse Kust Zuid 1&2 and chose the company as the preferred supplier for Hollandse Kust Zuid 3&4.

In November 2019, the developer chose Siemens Gamesa’s 11 MW turbines for all four offshore wind farms at the Hollandse Kust Zuid zone. For the 1.5 GW project, Siemens Gamesa will supply 140 wind turbines.

Based on the current schedule, all Hollandse Kust Zuid wind farms will be up and running at the end of 2022 or early in 2023.

Vattenfall secured the rights to build the Hollandse Kust Zuid 1&2 and the Hollandse Kust Zuid 3&4 wind farms in the first two subsidy-free offshore wind tenders in the Netherlands.

The developer signed an agreement for the Hollandse Kust Zuid 3&4 offshore grid connection with TenneT in mid-April. The one for Hollandse Kust Zuid 1&2 was signed in 2019.

The grid connection for the projects consists of two offshore transformer platforms, each with a 700 MW capacity and two 220 kV AC cables. TenneT is building a new onshore transformer station and is expanding the existing Maasvlakte 380 kV high-voltage station.